Yu. I. Choni – Ph.D. (Eng.), Associate Professor,

KNRTU – KAI

E-mail: tchoni@rambler.ru

L. K. T. Abuhadma – Post-graduate Student,

KNRTU – KAI

E-mail: LevAbuhadva@mail.ru

Currently, there is growing interest in the development of effective algorithms for retrieving the antenna radiation pattern (ARP) from measurements data taken in far from ideal conditions. Research on this topic has been started a long time ago and was purely theoretical in nature. Modern developments in this area are largely stimulated by the prospects for their practical application, primarily due to the emergence of the so-called vector signal analyzers – the measuring instruments that make it possible to take amplitudephase measurements in automatic mode.

With moderate quality of the radio frequency absorbing coating, the antenna testing taken in compact chambers is accompanied by reflections from the chamber walls in addition to the curved phase front of the irradiating field. In practice, auxiliary antennas with directional ARP are used, which reduces the intensity of the field reflected from the sidewalls of the camera. On the other hand, this increases the irregularity of the irradiating field within the test antenna area. The subject of this work is an analysis of the potential accuracy of reconstructing antenna pattern, with regard to the directivity of the auxiliary antenna.

The ideology of the used algorithm for the ARP retrieval results in two stages. At stage 1, the irradiating field is examined. For this purpose, the probe, whose ARP is known exactly, moves along the boundary of the working region S and the complex amplitudes {An} of the plane waves converging cluster, whose field approximates the real field in S, are calculated from the measured probe signals. At stage 2, they rotate the antenna under test, measure the signal received by it, and, knowing the spatial spectrum {An}, calculate ARP. As usual, the reconstructed ARP is sought in the form of an expansion in the selected number of basis functions.

The calculations show an interesting effect: even with a very moderate size of the auxiliary antenna, a collimating effect begins to appear, namely: the phase front of the emitting wave becomes flatter, and the measured angular dependence of the received signal approaches the exact ARP, although the increasing unevenness of the amplitude relief acts in the opposite way.

Simulation of measurement and data processing processes was carried out with reference to the following geometric proportions: antenna size is 10λ, distance to irradiator is 25λ, irradiator size varied from 0,25λ to 12λ. Calculations have showed that in the case of the antenna under test with the uniform amplitude distribution, the relative MSD before retrieval varied from 82% to 22%, while the potential (in the absence of noise) accuracy of the radiation retrieval is practically independent of the size of the auxiliary antenna and is of 4%. In the case of the antenna with an amplitude distribution decreasing on the edges, so-called cosine on the pedestal, similar values were 61%, 20%, and 2%, respectively.

The article provides texts of two Mathcad simulation programs. This provides the interested readers with the possibility to conduct their own research on the issue under discussion.

1. Choni Yu.I., Danilov I.Yu. Effektivnyj metod rekonstruktsii diagrammy napravlennosti antenny, izmerennoj v neideal'nykh usloviyakh. Antenny. 2016. № 4. S. 51–61.
2. Bakhrakh L.D., Kremenetskij S.D., Kurochkin A.P., Usin V.A., Shchifrin Ya.S. Metody izmereniya parametrov izluchayushchikh sistem v blizhnej zone. L.: Nauka. 1985.
3. Plokhikh S.A., Sazonov D.M., Shcherbakov V.I. Vosstanovlenie diagramm napravlennosti antenn metodom etalonnoj antenny po amplifazometricheskim izmereniyam v blizhnej zone. Izvestiya VUZov. Radioelektronika. 1987. T. 30. № 2. S. 59–64.
4. Choni Yu.I., Pirozhenko S.A. Vosstanovlenie DN antenny po rezul'tatam izmerenij v neideal'nykh usloviyakh. Izvestiya VUZov. Radioelektronika. 1992. T. 35. № 2. S. 43–50.
5. León G., Loredo S., Zapatero S., Las Heras F. Radiation pattern retrieval in non-anechoic chambers using the matrix pencil algorithm. Progress in Electromagnetics Research Letters. 2009. V. 9. P. 119–127. URL: http://www.jpier.org/PIERL/pierl09/14.09051204.pdf (data obrashcheniya: 12.07.15).
6. Yinusa K.A., Schmidt C.H., Eibert T.F. Scattering centers modeling of non-anechoic measurement environments. Adv. Radio Sci. 2012. V. 10. P. 69–73. DOI: 10.5194/ars-10-69-2012. URL: http://www.adv-radio-sci.net/10/69/2012/ars-10-69-2012.pdf (data obrashcheniya: 12.07.15).
7. Kalinin Yu.N. Izmerenie diagramm napravlennosti antenn v planarnom skanere bez izmereniya fazy. Antenny. 2015. № 1. S. 61–68.
8. Shkurkin M.S. Opredelenie trebovanij k tochnostnym kharakteristikam kompleksov blizhnej zony dlya izmerenij diagramm napravlennosti aperturnykh antenn. Izvestiya YuFU. Tekhnicheskie nauki. 2012. № 3. S. 101–107.
9. Zhao W. Retrieval of free space radiation patterns through measured data in a non-anechoic environment. PhD dissertation. Syracuse University, USA. 2013. URL: http://surface.syr.edu/cgi/viewcontent.cgi?article=1007&context=etd (data obrashcheniya: 12.07.15).
10. Krivosheev Yu.V. Izmerenie kharakteristik antenn v zone Frenelya na razrezhennoj setke uglov. Diss. … kand. tekhn. nauk. NIU «MEI». 2014. URL: http://www.mpei.ru/Science/Dissertations/dissertations/Dissertations/KrivosheevYV_diss.pdf (data obrashcheniya: 10.08.15).
11. Kirpanev A.V. Issledovanie antennykh sistem na osnove identifikatsii elektromagnitnykh polej. Avtoreferat diss. … dokt. tekhn. nauk. OAO «Kholdingovaya kompaniya «LENINETs». Sankt-Peterburg. 2008.
12. Choni Yu.I. Adjoint operator method and its aspects in regard to antenna synthesis. IX Proceedings of the 2013 IX International Conference on Antenna Theory and Techniques (ICATT). Odessa, Ukraine. 2013. P. 86–91.
13. Abukhadma L.K.T., Dardymov A.V., Lavrushev V.N., Choni Yu.I. Fizicheskij eksperiment po rekonstruktsii diagrammy napravlennosti antenny v ramkakh metodologii skhodyashchegosya puchka ploskikh voln. Zhurnal radioelektroniki (elektronnyj zhurnal). 2019. № 7. URL: http://jre.cplire.ru/jre/jul19/11/text.pdf.
14. Choni Yu.I., Abuhadma L.K.T., Danilov I.Yu. Antenna pattern retrieval from measurements in non-ideal anechoic chamber. 2018 Systems of Signals Generating and Processing in the Field of on Board Communications. Moscow, Russia. 2018. P. 376–382.
15. Abukhadma L.K.T., Choni Yu.I. Vosstanovlenie diagrammy napravlennosti antenny po izmereniyam v daleko ne ideal'nykh usloviyakh. Sb. «Materialy X Vserossijskogo konkursa molodykh uchenykh. Itogi dissertatsionnykh issledovanij». M: RAN, Mezhregional'nyj sovet po nauke i tekhnike. 2018. T. 1. S. 34–43.